1. Field of the Invention
The present invention relates to a coolant composition for a fuel cell, including (a) alkylene glycol, (b) deionized water, and (c) a compound containing a trimethylsilyl group.
2. Description of the Related Art
A fuel cell is an engine that produces electricity using electro-chemical reaction of hydrogen and oxygen, and heat is generated incidentally. Scores of KW class stack have been developed to apply fuel cell vehicles for drive system and heat generations per unit volume are increased according to high-capacity of the fuel cell, whereby there has been increasing an importance of the cooling.
To obtain a required electrical output from a polymer electrolyte fuel cell, the fuel cell is constituted as a cell stack having a construction of many single cells which are connected in series. Ideally, hydrogen as the fuel is converted to electrical energy. Actually, there is some electrical resistance in cell, whereby part of energy is converted to heat energy rather than electrical energy. Since the heat is generated in cell and the cell temperature increases, a cooling plate is inserted several cells for cooling the cell.
Meanwhile, deionized Water (DI-Water) commonly used in early development stage has high electric resistance and it is excellent in electric insulation and cooling performance. However, DI-water has disadvantages that it is frozen below 0° C. and has cold startup of fuel cell vehicles. In addition, there is a problem that ion in the fuel cell system is easily contaminated to decline electronic heat sharply.
For these reasons, there has been growing interest in the coolant for the fuel cell which is not frozen in the winter and has an excellent electric insulation. Mixture solution of water and alkylene glycols, e.g. monoethylene glycol and monopropylene glycol, was used as a coolant for conventional fuel cells.
However, there was a problem that glycols used in the coolant for conventional fuel cells as main base substance generate an ionic substance to increase electrical conductivity.
Accordingly, there are needs for antioxidants preventing or delaying the oxidation of main base substance.
Throughout this application, several patents and publications are referenced and citations are provided in parentheses. The disclosure of these patents and publications is incorporated into this application in order to more fully describe this invention and the state of the art to which this invention pertains.